Contents
1. Cylinder Numbering Fundamentals
Standard Longitudinal Layout (e.g., C7 S6 3.0T, B8 RS4 4.2L V8 logic)
- Bank 1 (Front Bank): Closest to engine accessories (pulleys, belts).
- Bank 2 (Rear Bank): Closest to the firewall (cabin).
- Cylinders numbered sequentially: 1-3 (Bank 1) | 4-6 (Bank 2).
Transverse Layout (e.g., B5 S4 2.7T, TT RS 3.2L)
- Bank numbering may reverse due to engine orientation.
- Bank 1 is typically the front-most bank (near the radiator).
2. Visual Reference (ASCII Diagram)
Longitudinal V6 (Viewed from Front):
----------------------------
| Bank 2 |
| [Cyl 4] [Cyl 5] [Cyl 6] |
| |
| Bank 1 |
| [Cyl 1] [Cyl 2] [Cyl 3] |
----------------------------
↓ Crankshaft Rotation (Clockwise)
3. Technical Nuances
OBD-II Correlation
| Cylinder | OBD-II Misfire Code | Common Faults |
|---|---|---|
| 1 | P0301 | Coil pack, fuel injector, vacuum leak |
| 2 | P0302 | Spark plug, intake gasket |
Note: Audi’s numbering differs from BMW (Bank 1 = left side in LHD) and Mercedes (sequential front-to-rear).
4. Common Mistakes & Myths
- Myth: “Bank 1 is always the driver’s side.”
- Truth: Depends on engine orientation (longitudinal vs. transverse).
- Myth: “V6 numbering matches inline-6 engines.”
- Truth: I-6 cylinders are numbered 1-6 linearly; V6 splits by bank.
5. Practical Applications
Spark Plug Replacement
- Bank 2 (rear) often requires more disassembly (intake manifold removal).
Turbocharged Engines (e.g., 3.0T)
- Cylinders 1/4 share a turbocharger in earlier models; later versions use twin-scroll turbos.
Warning: Incorrect cylinder identification can lead to misdiagnosis (e.g., swapping Banks 1/2 during coil replacement).
6. References & Further Reading
- Audi ELSA Pro (Service Manuals) – Section “Engine Mechanical > Cylinder Assignment”
- Audizine Forum: “V6 Cylinder Numbering Demystified” (Technical Thread)
- SAE J2012 – OBD-II Standardization
